Locomotive



R. F. HALL LOCOMOTIVE Dec. 18', 1923.

,Filed Feb. 21 1923 s Sheets-Sheet 1 WITNESS I R. F. HALL LCCQMOTIVE Dec, 18, 1923.. nmm z FiledFeb; 21. 1923 3 Sheets-Sheet 2 WITNESSES tons acting;

Patented Dec. l8, 1923.

UNETE STATES FHCCE.

earner or LOGOMOI'IVE.

Application filed February 21, 1923. Serial No. 620,428.

T 0 all whom it may concern:

Be it known that 1, ROBERT F. HALL, a citizen of the United States, and a resident of Schenectady, in the county of Schenectady and State of New York, have invented a certain new and useful Improvementin Locomotives, of which improvement the following is a specification.

My invention relates, generally, to 1000- motive engines of the type on which, through the intermediation of a cranked driving axle, more than two main or operating steam cylinders are installed, their pisto effect the rotation of the main driving w eels, as in those known as threecylinder engines, and, particularly, to the species of that type set forth in an application for Letters Patent of the United States, filed by me January 13, 1923, Ser. No. 612,406, now Patent No. 1, 464,931, granted Aug. 14:, 1923. In the locomotive disclosed in said application,-the centrecylinder is of less capacity than the outside cylinders.

. The object of my present invention is to enable the irregularity introduced in the turning moment by the inequality of cylinder capacities to be; substantially minimized' in practical service. p

The improvement claimed is hereinafter fully set forth.

In the accompanying drawings; Figure 1 is a diagrammatic side view of so much of a three-cylinder locomotive engine as illustrates an application of my invention; Fig. 2, a plan view of the same; Fig. 3, a front view,'in elevation; Fig. 4., a diagram showing the ideal equal angular relation of the three cranks of a three-cylinder loco- 'motive; Fig. 5, a diagram of similar character, showing the two outside cranks as 110 degrees apart, and the angle between I the centre crank and each of the side cranks as 125 degrees; Fig. 6, an ideal turning moment diagram for a three-cylinder engine, all the cylinders of which are of equal capacity, and with the cranks in the angu: lar relation shown in Fig. 4; Fig. 7, a similar diagram for a three-cylinder engine,the .centrecylinder of which is of less capacity than the outside cylinders, and with all cranks 120 degrees apart,,as in Fig. and, Fig. 8, an ideal turning moment diagram of a three-cylinder engine, having the centre cylinder of less capacity than either of the two outside cylinders, and with the two outside cranks 110 degrees apart, as in Fig. 5.

One of the principal advantages of the three-cyl1nder type of locomotive, is its uniform turning moment, as compared with i that of the two-cylinder type, and the lesser fluctuations of turning moment and tractive force, above their mean values, is less than in the twocylinder type, the meancylinder power can be greater, with respect to the weight on the driving wheels, than in the t 'wo cylinder type. By reference to Fig. 6. which is a turnin moment diagram for three cylinders, 0 equal capacity, and cranks 120 degrees apart, the even character of the turning moment will be apparent. The shape of the curve is influenced by the net pressure acting on the piston at any particular crank position, by the reation of length of main rod to the length of crank (or' the angularity of main rod), by the relation of the longitudinal axes of the cylinders to a horizontal plane through the centres of the driving axles, and also by the angularrelation of the cranksto each other. The inertia,of the moving parts also operates to change the character of the diagram, but as this tends to correct the unevenness, and also as its effect at low velocities is small, it was not considered in preparing the diagrams shown in Figs. 6, 7 and 8. The effect of the angularity of the main rods renders the diagram unsymmetrical, and for the sake of more clearly illustrating the principles involved, the main rod has been considered as of infinite length. The turning moment diagrams shown in Figs. 6, 7 and 8, differ somewhat from thosewhich form a part of the previous application, in that a difi'erent relation of cylinder capacity is used, and the not pressure urging the piston forward at the different points of the stroke are also difl'erent, At the lower part of each diagram is shown the separate turning-moment phases of each cylinder together with'the angular relation and- 5", 8, 8 and 8 are'for the centre cylinder, while-phases 4, 4: andAJ, 6, 6 and 6", 7, 7 and 7", 9, 9 and 9 are for the two outside cylinders.

invention is, herein exemplified as ap :plied in a three-cylinder single-expansion ocomotive having a central cylinder, 1, and two side cylinders, 1 1". .flhe pistons of all the cylinders'are, as in ordinary practice, coupled, by main connecting rods, '1, to crank pins, fixed in a crank, 9, and crank arms on driving wheels, 9, on a main driv- Min'g axle, 9., Steam is' supplied from the boiler,-11, to the distribution valve chests.- 2, of the cylinders, through which it is admitted;to,'and-exhausted from, the cyiin j ders, by the distribution valves, in the ordinary, manner. Various forms of valve gear, by which} the distribution valves may. be

. operated, to effect the cut-off desired, are

Well known in standard practice, and not, in and of themselves, forming part of my present invention, are not herein exemplified.

In orderto eliminate, or reduce to the lowest degree pi'actic'able the lack of uniformity in turning moment, in a three-cylinder engine, the centre cylinderot which is of less capacity than the outer cylinders, which will be indicated by a comparison of the diagrams, Figs. 6, 7 and 8, as presently to be explained, the ou'tei crank arm pins fare, under my invention, as indicated in Fig. 5. disposed at an angle which is less than one-third of the circumference of their stroke, as, say, one of 110 degrees, and at equal angles, as, say, 125 degrees, to the crank pin of the centre cylinder.

Referring to the diagrams, Fig.- 7 is a turning moment diagram of a three-cylinder engine of approximately equal power 4.0 that of which a'turning moment diagram is shown in Fig. 6." In this diagram, however, thecentre cylinder is less in capacity than the twooutside cylinders, but all cranks are 120 degrees apart as in Fig. 6. Fig. 8 is a turning-moment diagram of the same cylinders as those in Fig. 7, but with the two outside cranks 110 degrees apart instead of 120. It will be noted in Fig. 7 that phases '11 and let of thecombined turning-moment diagram are lower, and that phases 103,12, 13 and 15, are higher in relationto the mean turninganoment line 16"--16 than the COI.- responding phases 11 and 14, and 10, 12, 13 and 15 are to line 161(3 in Fig. (3. The

[together is shown in Fig. 8 and consists in said cylinders to the crank arms of efi ect of bringing the outside cranks closer in bringing the turning .inoment' phases at" and 6 and 7} and- 9 closer. to each other than 4 and 6, and 7 and 9 in Fig. 7, with the result that phases 11 and lt -a're higher, while phases 10 12*,13" and 15 are lower than the-corresponding phases in Fig.

This results in a more even turning moment and one which has a less fluctuation above and below its mean value than that shown in Fig. 7.

While "Fig. 5 shows 110 degrees between thetwo outside cranks and an equal angular spacing of 1:25 degrees between the centre crank and the two outside cranks, these relations may be varied without departing from the spirit of my invention. ,For example, with some conditions of main rod tre crank and the two outside. cranksniay shown in Fig. '5, v

either be made equal, as or unequal.

I cla m as my'invention and ClQSll'B to se cure by Letters Patent:-

1. In a single-expansion locomotive, the

combination of a cranked driving axle; end

crank arms, fixed thereon, at an angle less than 120 degrees; a central cylinder and twooutside cylinders, the capacity of the central cylinder being less-than that of either of the two outside cylinders; and connections, coupling the pistons of said cylinders to the crank arms of the driving axle. Q

2. In a single-expansion locomotive, the

combination of a cranked driving axle; end crank arms fixed tliereoi ,-atan apgle less than 120 degrees and .at unequala'n'gles to the crank of the driving axle; a central cylinder and two outside cylinders, the capacity of the central cylinder being less than that of either of the two outside cylinders; and, connections, coupling the pistons of the drivingaxle. 3. In" a single-expansion locomotive, the combination of a cranked driving axle; .end crank arms fixed thereon, at an'angle of substantially 110 degrees; a central cylinder and two outside cylinders, the capacity of the central cylinder being less than that of either of the two outside cylinders; and connections. coupling the pistons of said cylinders to the crank arms of the driving axle. v I ROBERT F. HALL.

Witnesses:

C. K. Gn'roHnLL, B. C. FABosicAY. 

